Telephone-exchange system



C. B. FOWLER.

YTELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED 11111.24, 1919.

1,371,749. A Patented Mar.15,1921.

75 Ofee/r's /M Ven /U/f: Vd/fe we e 5. FUW/e/ A ffy.

UNITED STATES PAT-ENT reinaA CLARENCE B. FOWLER, OF- NEW YORK, N. Y.,SSIG-NOR 'TO-NESTERN ELCTRC CllfiI- PANY, NCORPORATED, OF NEW YORK, N.Y., A CORPORATIGN OIF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Speccation of Letters Eatent.

Application lefl anuary 24, 1819. Serial No. 272,798.

fo ZZ whom it may concern Ee it known that I, CLARENCE B. FowLnR,

a citizen of the United States, residing at New York, in the county ofNew York, State of New York, have invented certain new and usefulImprovements in Telephonelxchange Systems, of which the ollowingV .is afull, clear, concise, and exact description.

kThis invention relates to telephone eX- change systems and moreparticularly to a 'line circuit for use in such systems.

Vassociated with an operators cord circuit to indicate that adisconnection is desired. In accordance with this feature or'. theinvention a relay, which is responsive to alternating' signalingcurrent,` is arrange-:l to coperate with a relay normally disconnectedfrom the line to control a supervisory signal connected with theoperators connecting circuit when the connecting circuit is associatedwith the subscribers line. This and other features of the invention notspecifically rerperred toaboye will be apparent from the followingspeciiication.

The drawing shows diagrammatically a telephone line circuit and aportion of an operators cord circuit adapted to coperate therewith. ltis thought that the invention may be best understood from the followingdescription of the operation of the circuit shown in the drawing.

The subscriber at substation A, desiring to initiate a call, removes theusual Vtelephone receiver from the hook switch and opera-tes the magnetogenerator' indicated at l. The operation of the generator impressesalternating signaling current on the following circuit: trom oneterminal of the gencrater l to one conductor of the lline 2, through theleft-hand winding of the relay 3, back over the other conductor of theline 2 to the other terminal of the generator.

The relay 3 in operating closes a locking circuit for itself, whichmaybe traced from battery through the right-hand winding or" the relay3, through the normal contact of the jack 9, outer armaturevand contactor" relay 3 to ground. .The relay 3 also closes a circuit for the linesignal, which may be traced from battery, through the line lamp 5,lett-hand armature and normal contact of the relay 4, inner armature andContact of the relay 3 to ground.v The operator, upon observing theillumination of the signal 5, inserts the plug 8 of one of a pluralityof cord circuits at her position into the jaclr 9. The insertion oitheplug- S opens the normal Contact ci the jack, which was included in thelocking circuit of the `relay 3, causing the release of such relay.Shortly Patented Mar. i5, 4921,. Y

thereafter the alternate contact of the jack i is made, thus preparing acircuit` for the slow-to-operate relay 4 upon the subsequentenergization of the relay 3.

lt will be observed thatuntil the enerH A gization of the relay 4, nopotential is present upon the sleeve of the jack, kand consequently, theinsertionof the plug S into the jack 9 will have no eii'ect upon thesupervisorylamp 6. The operator, uponV ascertaining thedesired numberthrough the actuation of listening hey l0 establishes a conuection inthe usual manner. At the termie nation of the conversation thesubscriber A Vwill again operate the generator l toy indithe generator'1, the relay 3 will'be energized as before described, but since atvthis time the plug S is in the jack 9 the following circuit will loeAclosed, from battery through the relay v4,.through the alternatevContact of the jack 9, contact and outer armature of the relay 3 toground. The operation of the Vrelay 4 will prevent the display of theline signal 5 as a circuit therefor is openedl at the left-hand armatureand contact of the relay 4. At its inner iight-hand armature, the relay4 closes a locking circuit for the relay 3, which may be traced frombattery through the right-hand Winding of the relay 3, contact and innerright-hand armature of the relay 4 to ground.

A circuit for the supervisory lamp will be closed which extendsl frombattery subscribers line to normal, rea-dy for use in connection withanother call. y i

inasmuch as it is contemplated that the line circuit of the inventionmay terminate at an exchange equipped with cord circuits arranged forcommon battery working, there is inserted inthe line intermediate theconnecting point oit the line relay 3 and the jack 9 a pair otcondensers T. These condensers prevent the. operation or locking up oirelay 3 by battery connected across the ring` and tip conductors of thecord circuit When the plug 8 is inserted in the jack 9.

1What is claimed is:

l. ln a telephone exchange system, a line circuit, a Vlink circuit forconnection therewith, a locking` relay associated with the line, asignaling device controlled thereby, means responsive to the connectionof the link circuit with the line circuit to open the locking circuit ofand thereby release the relay, and means cooperating.therewith toprepare another locking circuit for use by the relay upon a subsequentcncrgization thereof.

2. In a telephone, exchange system, a line circuit, a link circuit forconnection there- With, a locking relay associated with the line, asignaling' device controlled. thereby, tivo locking circuits for therelay, and means controlled by the connection and disconnection of thelink circuit lwith the line circuit for determining the locking circuitto be used by the relay. y

$3. In a telephone exchange system, a line circuit, a link circuit forconnection therewith, a relay associated with the line circuit, asignaling device controlled thereby, a supervisory` signaling deviceassociated with the link circuit, means responsive to the connection oithe link with the line for removing' the line signaling device from thecontrol of the relay, and a circuit for the supervisory signaling deviceadaptedv to'be closed upon a. subsequent enelgizatiou of the relay.

4i. in a telephone exchange system, a line l circuit, a link circuit forconnection therewith, a, relay associated With the line circuit, asignaling device controlled thereby, a supervisory signaling deviceassociated With the link, means responsive to the connection oit thelink with the line for removing the line signaling device from thecontrol of the relay and tor releasing the relay, additional meanscoperating therewith" to prepare a circuit for the supervisory signalingdevice, and further means responsive to a subsequent.energization oftheline relay during the connection to `complete the operating'4 circuitot the sigipervisory signaling device.

In a telephone exchange system, a line circuit terminating in a jackhaving a normally disconnected sleeve contact, a link circuitterminating in aplug ttor connection therewith, .a relay associated Withthe line circuit, a, signaling', device associated With the linkcircuit, and means jointly controlled by theconnection of the plug withthe jack and by an energization of the relay for connecting a source otcurrent With the sleeve.

ated with the telephone line, but normallyV disconnected therefrom,coperating with the line relay for actuating the supervisory signal whentheplug ot' the link circuit is inserted in the jack of the line circuitto actuate the supervisory signal when a disconneet signal istransmitted over the telephone line.

In Witness whereof, I hereunto subscribe my name this ilthday ofJanuary, A. D.

1919. CLARENCE B. FOWLER.

